A not so cool noise.

[Korndogg]

On my truck (99 silverado 1500) after about an hour or so of driving a weird rubbing noise starts and gets really bad. It almost sounds like two pieces of metal touching but it's not a grinding it's more of a "whirling" noise. I'm thinking it might be a hub but it doesn't change pitch when I turn left or right.

It also comes and goes, it isn't steady.

I know its not the best description but any ideas?

[WickedSix]

my first suspects would bearings or possibly a race spinning in its housing...come under load? unload? off the gas? on the gas? front of vehicle? rear of vehicle?

[Korndogg]

Sorry yeah its the front. It really doesn't matter if it is under load or not, it just starts all of a sudden. It's like it heats up or something and does it since it takes an hour to happen usually.

[WickedSix]

but it is a rotational noise that varies with wheel speed and not engine rpm? points toward the front diff... even though 4wd isn't engaged the cv axles still spin in the diff housing and one actually drives the spider gears in the differential itself...lots of possible metal to metal contact under heat....check your fluid level first, then the color, and the smell...burnt gear lube smells even more accrid than regular....

[Korndogg]

Yeah I was worried about that. Honestly if this is anything that is going to be too expensive I'm going to sell the truck and get something else. I'm due for a new vehicle lol.

[Wagonbacker9]

.burnt gear lube smells even more accrid than regular....

no, just a different flavor of "the most awful smelling shit in the universe".

Yeah I was worried about that. Honestly if this is anything that is going to be too expensive I'm going to sell the truck and get something else. I'm due for a new vehicle lol.

Hah... I wish. Thats almost as good as my friend who trades in so he doesn't have to buy new tires.

[PonyKiller87]

Sounds like a hub to me, my old S10 started doing that here and there after long trips, right before the front hub started grinding.

The first time I heard it I thought it was a tornado siren, I pulled over stopped, it went away and I thought wow, that was an odd time to do a siren test, lol. Mine would always go away after stopping for a min, but like I said it wasn't long after that when the front hub started grinding pretty bad.

[Korndogg]

LOL yeah it does kind of sound like a siren. It's just weird to me that it does it only after like 45min to an hour and then when i stop for a while and drive again it takes that long again. Never heard anything like it before.

[brotherbenn83]

no, just a different flavor of "the most awful smelling shit in the universe".

Incorrect, as noted on the bottles...GM synthetic gear lube has "new grape scent"

[Wagonbacker9]

A buddy of mine did a diff fluid change in my garage 2 weeks ago, and it STILL stinks in there.